UN Secretary-General Ban Ki-moon and the international envoy for Syria, Lakhdar Brahimi, have criticized "outside powers" for supplying arms to both the government and rebels in Syria.
Meeting in New York on January 21, Ban and Brahimi did not name any countries.
Russia and Iran, however, have supplied weapons to the government of Syrian President Bashar al-Assad. The Syrian government accuses Qatar, Turkey, and other Persian Gulf states of arming the opposition.
The comments come as UN humanitarian organizations complained the international community is failing to provide the aid Syrian refugees need.
"Our donors' community, our international donor community, are only giving 50 percent of what is needed here is in our mind very, very upsetting and of course the results stand in much higher humanitarian suffering than needs to be," said John Ging, operations manager for the Office for the Coordination Of Humanitarian Affairs (OCHA), who was speaking January 21 in Damascus during a fact-finding trip to Syria. "That means that the people who need the food, not all of them are getting the food and so on. We are really wishing to reenergize our donor community."
Ging called on all parties involved in the conflict to seek a solution to the crisis.
"We are not working on resolving the conflict but others are, others have a responsibility in political forums to find solutions," Ging said. "Those who are involved in the conflict, let's be very clear, have supporters. So they need to get together and sort themselves out in terms of bringing this conflict to an end that's the demand that we are hearing everywhere."
The UN is hoping to raise $1.5 billion to fund Syria at a donors' conference in Kuwait on January 30.
According to the UN, more than 60,000 people have been killed in Syria's nearly two-year-old conflict, at least 600,000 have become refugees, and 2.5 million are suffering from hunger.
On the ground inside Syria, activists said some 30 people were killed late on January 21 in a suicide car bomb attack in Salmiyeh, in the central province of Hama. Activists said most of the dead were members of a pro-regime militia.
The fresh violence came as Russia announced it would evacuate some of its nationals from Syria starting later on January 22.
Based on reporting by dpa and Reuters